As used herein, the term "movie" refers to both a series of image frames and their display, which gives the appearance of motion. Most image frames in the series are only slightly different from the image frames immediately preceding and succeeding them. Successively displaying the series of image frames in sequential order gives the appearance of motion.
There are two common methods of creating a digital movie. The first is to have an artist manually create each individual image frame required in the movie, using a process analogous to painting individual pictures. In order to make the movie interactive, the artist would need to create several different series of images, so that at different points during the display of the movie, the user could choose from among alternate subsequent series. The alternate sets of images would depict different action according to the choice that the user would input to the display apparatus.
While this technique allows for highly detailed, bit-mapped graphics to be incorporated into the image frames of the movie, the time required for an artist to individually create each image frame is cost prohibitive for all but very short digital movies.
Another method of creating a digital movie is to create a three dimensional virtual environment in a computer system. In the environment, series of mathematical equations represent the shapes and surfaces of all of the elements in the environment. The environment can be displayed by enabling a user to move a virtual camera through the environment in real time. This method generally provides more movement options to the user than does the hand drawn production technique.
However, this method requires enormous computing power if finely detailed elements of the environments are to be displayed. To reduce the computing requirements, surfaces of the elements are detailed with a process called texture mapping, which requires less data to be displayed, but does not provide as detailed a surface as bit-mapped graphics.
The present invention combines the benefit of the highly detailed, bit-mapped graphics of the manually produced digital movies, with the benefit of the versatility of the virtual environment produced digital movies, yet does not suffer from the associated drawbacks of requiring the labor intensity of individually drawing each image frame, or of reducing the detail of the image frames.